Add an ui overlay on center view with a 2 axis handle control ton control rotation and compression.

Maybe something like this:

O 1)
|
| 3)
- - - O-------O - - - - - -
2)

Where handle 1 is used to drag in the vector direction to increase/decrease the compression, handle 2 is used to drag and dropwhich affects the offset and the last handle (3) is used to rotate around center of vector.

the - - - - - - is a helper line that runs from edge to edge to indicate the split offset in the image.